Yes, it is generally true that knives can lose their edge quicker when put in a dishwasher compared to hand washing. There are several reasons why this happens:
Aggressive water pressure: Dishwashers use high water pressure during the wash cycle, which can cause the knives to collide with other utensils, dishes, or the dishwasher's interior. This constant knocking and jostling can lead to micro-chips or dulling of the knife edge over time.
Chemicals and detergents: Dishwashing detergents and chemicals used in dishwashers can be abrasive and harsh on the knife blade. These substances can erode the knife's sharp edge, leading to faster dulling.
Heat and humidity: Dishwashers use high temperatures and humidity during the cleaning process. This environment can cause the metal of the knife to expand and contract rapidly, potentially affecting the blade's integrity and sharpness.
Improper placement: If knives are not properly placed or secured in the dishwasher, they can rub against other utensils or the dishwasher's racks, resulting in friction and potential damage to the edge.
To help preserve the sharpness and longevity of your knives:
Hand wash knives: It is generally recommended to hand wash knives with mild dish soap and warm water. This allows you to have better control over the cleaning process, ensuring gentler handling and avoiding the harsh conditions of a dishwasher.
Proper storage: Store knives in a knife block, magnetic strip, or knife sheaths to protect the blade from coming into contact with other utensils and prevent accidental damage.
Hand dry: After washing, thoroughly dry the knives with a soft cloth or towel to remove any moisture and prevent rust or corrosion.
Regular honing and sharpening: Use a honing steel or sharpening stone to maintain the edge of your knives regularly. Honing realigns the edge, while sharpening removes a small amount of metal to restore the blade's sharpness.
By adopting proper care and maintenance practices, you can help extend the sharpness and lifespan of your knives, regardless of whether they are dishwasher-safe or not.